The present invention relates to a centrifuge with a drive-mechanism that incorporates a vertical spindle mounted on at least one bearing in such a way as to rotate while aligning itself in space around a point of attachment on its longitudinal axis with respect to the framework of the centrifuge and with respect to a bearing housing that is supported on the framework, with the spindle driven by a belt.
A centrifuge of this type in which the V-belt pulley that powers the spindle is mounted under the step bearing, so that the midplane of the belt drive is below the bearing, is known from German Auslegeschrift No. 1 031 222. One drawback to this device however is that the forces applied to the spindle by the pull of the belt tend to skew it. Another is that the self-aligning emplacement of the spindle, which consists of a number of small parts, helical springs distributed around the neck bearing and a resilient support and a bearing ring at the step bearing, is expensive. Furthermore, since the distance between the step and neck bearings is long, the spindle must be so lengthy that its mass will have an excessive effect when the machine is in operation.